This invention relates to a moving yoke, particularly but not exclusively for supporting a light, mirror, television monitor, camera or any other device for sending or receiving electromagnetic radiation.
It is known to provide automated lighting including a moving yoke to support the light source. The yoke of this known lighting comprises a platform swivellable about a vertical axis through 360xc2x0 and support arms upstanding from the platform which support a housing containing a light source for pivotable movement through less than 360xc2x0 about a horizontal axis. This yoke allows a light source to be swivelled through 360xc2x0 with the swivel axis extending in a plane which bisects the light source and also allows the light source to be pivoted about the horizontal axis.
The present invention seeks to provide a more versatile yoke which allows additional movements to take place.
According to the present invention there is provided a moving yoke comprising a first yoke member, a second yoke member swivellable relative to the first yoke member about a first axis, the second yoke member having an arcuate support portion, and a third yoke member having an arcuate portion, which is supported by the arcuate portion of the second yoke portion to enable slidable movement relative thereto along an arcuate path.
Preferably, the third yoke member also has means for supporting an object, such as a light, for pivotable movement about a second axis. In this case, conveniently, the third yoke member can be arranged in a position relative to the second yoke member such that the second axis is perpendicular to, and coplanar with, the first axis and can be moved from this position through an arcuate path of 90xc2x0 in order to bring the second axis parallel to, and offset from, the first axis.
Preferably, the yoke includes means, typically in the form of electric motors, for power operably swivelling the second yoke member relative to the first yoke member about said first axis, for sliding the arcuate portion of the third yoke member relative to the arcuate portion of the second yoke member and, where the third yoke member has support means, for pivoting the support means about said second axis.
Conveniently, the third yoke member includes an arcuate rack engageable with at least one pinion gear which can be rotated to move the third yoke member relative to the second yoke member along said arcuate path. In this case the pinion gear is, preferably, rotatable by an electric motor supported by the second yoke member.
The third yoke member may comprise two parts rotatable relative to one another. In this case, one part may include the rack and the other part may include the support means.
In one embodiment, the support means of the third yoke member supports a light source.
The invention will now be more particularly described, by way of example, with reference to the accompanying drawings.